Each day a different image or photograph is featured, with an
accompanying caption, which deals with various topics in Earth Science.

Exfoliation of Half Dome

Half Dome, shown above on June 10, 2004, is located in Yosemite National Park, California. This huge granitic rock illustrates the process of exfoliation, where concentric scales, plates or flakes of rock material are successively stripped from the surface of a rock mass. In this case, the process results from the release of pressure of a large block of granite that was previously burried. In essence, when Half Dome was forced to the surface, pressure was released and it slowly expanded -- the interior rock pushing outward.

This photo shows the east side of Half Dome. Note the trees on the top of the ridge, indicating the massive size of the "scales."